#include<vector>
#include<iostream>
using namespace std;

class Test {
private:
	friend void gunc();
	void func() {

	}
};

void gunc() {
	Test t;
	t.func();
}

int main() {
	int a = 0;
	int b = 0;
	int& lr = a;
	lr = b;

	int&& rr = 5;
	rr = 6;

	std::forward
}
